A really nice screen saver that has been around for a while. I always wanted a real clock like this, but never got the chance to get it (someday maybe). So in the meantime - I found this one.
I like it because it's simple, it has big display and you can easily see it from across the room (although you can zoom out and make it smaller). Changing digits resembles the real thing - meaning that you get that "flip over" effect. Nice touch!
You can get it at http://www.9031.com/downloads/screensavers.html